Answer
Answer: C
Work Step by Step
$ 3(x+2)^{2}+4=13\qquad$ ...add $-4$ to each side.
$ 3(x+2)^{2}+4-4=13-4\qquad$ ...simplify.
$ 3(x+2)^{2}=9\qquad$ ...divide each side with $3$.
$(x+2)^{2}=3\qquad$ ...take square roots of each side.
$\sqrt{(x+2)^{2}}=\sqrt{3}\qquad$ ...simplify.
...When solving an equation of the form $x^{2}=s$ where $s>0$,
we find both the positive and negative solutions.
$ x+2=\pm\sqrt{3}\qquad$ ...add $-2$ to each side.
$ x+2-2=\pm\sqrt{3}-2\qquad$ ...simplify.
$x=-2\pm\sqrt{3}$
